1. Field of the Invention
This invention relates to a pressure connection device for a connector provided with a plurality of contacts in alignment and adapted to shear and squeeze electric cables into the contacts of the connector to establish electrical connection.
2. Description of the Prior Art
There has been known a pressure connection device of this type, which comprises, as illustrated in FIG. 6, a holder adapted to secure in position a connector 1 having a plurality of pressure contacts 11 in alignment, a pressure connecting rod 4 which moves toward the pressure contacts 11 of the connector 1 so as to press each electric cable 2 into the respective pressure contacts, a cutter which is moved in the direction of the contacts 11 (hereinafter, termed as "advance" or "move forward") in a state slidable on the pressure connecting rod 4, and a cutter rest 9 for supporting the cutter 8.
The aforementioned conventional pressure connection device has suffered the various drawbacks as described below.
(1) The cutter rest 9 should be formed of metallic material having strength enough to support the cable 2 to be cut and the cutting edge 81 of the cutter 8. However, the cutting edge 81 is markedly susceptible of abrasion because the cutting edge comes into collision with the cutter rest 9 immediately after shearing the cable.
(2) The positioning of the cutter 8 in relation to the cutter rest 9 is very difficult. If the side surface 91 of the cutter rest 9 is brought much too close to the side surface 15 of the connector 1, the connector is laterally energized by the cutter 8 and displaced, to thereby cause incompleteness of an electrical connection. If the distance between the side surface 15 of the connector and the side surface 91 of the cutter rest 9 is enlarged, the cutter rest fails to securely support the cutter edge 81, with the result that the cutter becomes dull and renders the precise shearing of the cable difficult. Thus, the provision of the cutter 8 and the cutter rest 9 is also difficult.
(3) Even if the slide surface 82 of the cutter 8 assumes its position lower than the surface 15 of the connector 1 in order to prevent the cutter edge 81 from causing damage on the side surface 15 or the connecting surface 12 of the connector, the cable 2 becomes possessed of a sheared edge protruding outwardly from the surface 15 thereof when it is sheared by the aforementioned cutter. Because the protruding end of the cable is tangible, the connector of this construction incurs danger and has a possibility that an irregular operation will occur in an electric device using this connector. Even if an attempt is made at using a covering case to eliminate the aforementioned disadvantage, the sheared end protruding from the side surface 15 of the connector prevents the covering case from being mounted on the connector, and consequently, it is impossible to shield the sheared end of the cable.
(4) In the case of a small-sized connector, the front surface 41 of the pressure connecting rod 4 cannot acquire ample area on which the cable 2 is supported, thereby making it impossible to secure the cable. As a result, only the cable core within the cable is drawn and slips out of place in shearing the cable, thereby frequently causing imcomplete electrical connection of the cable to the contacts of the connector. Particularly, when the cutter becomes dull, this disadvantage becomes conspicuous.
(5) The replacement or polishing of a worn-out cutter is often required because the cutter edge 81 is easily worn. In addition, every time the cutter is removed, therefore, troublesome positioning work for the cutter 8 is necessary.